This study aims to examine the relationship between social connectedness and prevalent HIV infection among low-income individuals who have heterosexual sex in Baltimore, Maryland. Studies have begun to explore the relationship between social, economic, and physical characteristics of individuals' neighborhoods and HIV risk behaviors and HIV prevalence/incidence. A commonly measured social environment variable is "social connectedness," defined as the magnitude and quality of an individual's social network, and its ability to work toward common goals. The specific aims of this study are to (1) develop valid and reliable scales to measure (a) perceived powerlessness and (b) the importance of sex and sexual relationships in self-validation and (c) to modify and validate existing social connectedness scales for use in low income neighborhoods, (2) determine whether social connectedness is associated with both HIV infection and HIV high risk behaviors and whether the association is mediated by psychosocialfactors (perceived powerlessness and the importance of sex and sexual relationships in self-validation) in low income neighborhoods and (3) if the relationship between social connectedness and HIV risk behaviors and prevalent HIV infection is modified by neighborhood disorder in low income neighborhoods. In line with the NIMH's research areas of high priority, the aims of this study are designed to better understand the roles and interactions of individual- and community-level social factors associated with HIV infection for the purpose of targeting risk-reduction strategies to individuals living in low-income neighborhoods.These aims will be studied through the BESURE study, the Baltimore site of the National HIV Behavioral Surveillance System. The study population is individuals having heterosexual sex at high risk of HIV infection. 750 men and women living in HIV high-risk areas in Baltimore City will be asked about social connectedness, perceived powerlessness, and the importance of sex and sexual relationships in self-validation using scales. Serum specimens will be collected from consenting participants for enzyme immunoassay screening, with a confirmatory Western blot. The effect of social connectedness on each study outcome will be analyzed using multi-level modeling adjusting for individual and neighborhood level factors. [unreadable] [unreadable] PUBLIC HEALTH RELEVANCE: This study will provide information about whether social connectedness is a low cost factor that should be targeted for intervention among low income individuals. Interventions such as community centers and other structural interventions to improve social connectedness could be more cost effective due to their ability to reach a wider audience while simultaneously impacting multiple diseases. [unreadable] [unreadable] [unreadable]